Track for track-laying vehicles



Oc't. 23, 1945. R. s. GARBER TRACK FOR TRACK-LAY'ING VEHICLES Filed Sept. 5.0, 1943 ATTORNEY `Patented Oct. 23, 1945 l `V s TRACK Fon. TRACK-Larme VEHICLES.

Ray S. Garber, Montreal, Quebec, Canada, as-

`signor tov United States Rubber Company, New

York, N. Y., a corporationzofliew Jersey Application September 30, 1943 Serial No.. 504;424`

In Canada ctober 31 1942 3 Claims.. (Cl. 30S- 10) l assembly of the track and the replacement oi?` `\In endless articulated tracks used heretofore in track-laying vehicles,` the joints therein have been provided with rubber bushings around the connecting pins. Such bushings have been positionedl in the tread blocks or inl both the tread blocks and, the connecting links. In such construction, substantially the entirelength of the connecting pins is surrounded with rubber bush-l ings, andas the rubber is resilient, the pins can bendwithin the surrounding rubber from end to end, `similar to the case where a. beam is supported at each end and the load is carried in the middle.`

lIn accordance with the present. invention, the tread blocks are provided with recesses on their opposite sides having end walls between which the ends of links connecting the adjacent blocks are pivoted on pins extending from one side of the block to the other and passing through rubber bushings in the ends of the links. In this construction, the pins are rmly anchored in the `end walls of the recesses, and the ends of the bushings are placed in closely spaced relation to ,the end walls of the` recesses, with the result that the pins are firmly supported in the blocks at relatively short intervals which prevent them from bending. Another advantage of this construction is that the bushings are positioned in the links which are smaller-thanthe blocks, and consequently it is easier and less costly to` replace a. wornout `bushing than it would be if it were located` in the block. Furthermore, the links can be readily replaced in the eld because the pins are located in openings which extend through the blocksand can beeasily driven out of the blocks for the replacement of the links.

Anembodiment ofthis invention is hereinafter described in reference to the accompanying drawing" in which:

lis a plan View partly in section of a portion of a track for a track-laying vehicle ernbodying this invention, and showing a single tread blockand 'its connecting links; l

2` is a side-view of a portion of the track, or an end view of twoof the blocks and the connetting` links, with parts insection;

Figs. 3, is a side-elevational view of one oi* the tread blocks, showingthe relation of the bogie wheels which support the vehicle,` the driving sprockets, and the` ground supporting surface in respect to the treadblock; and

Fig. 4 is an enlarged cross-sectional view of a modification of `the invention, taken through a connecting link, a resilient bushing, and a connecting ein.

Referring to the drawing, the trackas illustrated herein has aplurality of tread blocks I0 connected by a plurality ot links l I, so as to form an endless articulated track, and to provide a pivotal movement between the blocks to permit them to pass around the driving sprockets I2 shown in` Fig. 3. Such sprockets' are placed ,at one end of the. track, in accordance with the usual,` construction and such relationship is `there fore not shown. The vehicle is supported on the outer periphery I 3 of thebogie wheels I4 (only one being shown in Fig. 3), which travel on the flat surfaces VI5 of the tread blocks Ill.v The tread blocks I0 are provided with the usual recesses I6, with which the sprocket teeth I1 mesh, and with guide projections .IB which keep the track in alignment with respect to the bogie Wheels I4 and the sprockets I2. For the purpose of simplifying the illustration of the invention,

only the outer circumferences of the sprockets I2 and the bogie wheels I4 are shown.

The opposite sides of the blocks are provided with recesses I9 having end walls 20 between which the connecting links I I are pivoted on pins 2|, which extendthrough the recesses I9, and

i 4are securedl against rotation in openings 22 in the end Walls 2,0 on the opposite sides of the recesses IS. `The recesses I9 form in conjunction with the openings 2 2 continuous passages or Openings through the tread blocks I0 for the reception of continuousipins 2|.`

EaQhof-the endsof the links II isprovided with a resilient bushing 23, which may be elastic rubber, either natural or synthetic, or theI like. The outer radial surfaceM of the resilient vbushing 23 is secured against rotation in respect to theonnecting ,link Il, and its inner radial surface is secured Yagainst rotation in respect to a metal bushing 25, through which, the connecting pin 2i extends and'is secured against rotation in respect theretol Any of the known methods may be' used for securing the rubber bushing 23 A asa-inst ,rotation in respectto the link I I and the metal bushing 25, such as by forming a vulcanizing bond between these members, O by ad-v hesively securing the rubber to the metal, or by forcing the rubber into the bore in the link II between it and the metal bushing 25. Relative rotation between the pin 2| and the openings 22 in the block I and the inner radial surface of the bushing may be prevented by the frictional engagement of the pin with these parts,

such as `for `example "by forcing the Vpin in the openingswith a tight but removable t.

For the purpose of reducing the maximum torsional stress imparted to the rubber bushings 23 when they pass around the sprockets I2, or

end supporting wheels of the track, the bushings are subjected to initial torsional stresses'in the proper direction when the centers of the -bushings in the same link I I lie on the line connectingV the centers of the pin openings 22 in the blocks IIJ, to' which the links are connected. To accomplish the above, the pins 2| are driven through the bushings 25 when the angular relation of the links II and the blocks I6 are such that after being moved until the centers of the bushings in the same link and the centers of the openings 1 in the connected block lie in a straight line, then half the maximum angular movement of the` links I I in respect to the blocks IIJ during their travel around the sprockets I2, or the end supporting wheels of the track. i

The pin 2| may be secured against rotation in respect to the block I0 and the inner metal bushing 25 by making the openings 22 in the blocks.

and the opening in the bushing 25 of a noncircular shape, such for example as hexagonal in crosssection,rand making the pin of the corresponding shape and slightly smaller in size, as shown in Fig. 4, which is a cross-sectional view of a modied form taken through the connecting link 26, rubber bushing 21, inner metal bushing 28, and pin 29, corresponding to the similar members in Figs. 1 and 2. The rubber bushing 21 may be formed separately from the link 26, and provided with an outer metal shell 30, which may be subsequently shrunk and forced into the bore 3| in the end of the link 26, so as to compress the rubber 2l by shrinkage of the shell 30 and also to form a pressed t between the shell 3Uand the bore 3| in the link 26, and thereby secure the outer radial surface of the rubber bushing 21 from rotating in respect'I to the link 26. The outer and inner radial surfaces of the rubber 26 may be secured against rotation respectively in respect to the outer shell and the inner metal, bushing 28 in accordance with any of the methods described in reference in Figs. 1 to 3.

Where the pin 29 and the openings into which it fits is of aV non-circular, or hexagonal shape as shown, it is not necessary to provide as tight a fit between the outer surfaces of the pin and the walls of the opening as in the case where the pin and the openings are of a circular shape as shown in Figs. 1 to 3, in order to prevent the rotation ofthe parts with respect to one another. The pins 29 may be secured against longitudinal movement with a set screw, or the like extending through the walls of the opening 22 in the block I0 and against the pin 29.

As shown in Figs. 1 to 3, two links II are arranged side by side on the opposite sides of the blocks II) so as to connect the blocks with dual parallel rows of such links. A projection 'of metal 32 on each side of the blocks I0 separate the rows of links. The opposite sides of the projections 32 form the adjacent end walls 20- of the adjacent recesses 'I9 into which the ends ofthe links II extend. If desired, a single row of links could be used, but in order to provide a large rubber supporting area and at the same time firmly support the pins in the blocks I0 at relativelyv closely spaced points, it is desirable `to use more than one row of links.

' Another' advantage of this track construction is that 'the recesses I9 are provided with top walls 33 and bottom walls 34 which protect the links I I and their bushings from engagement with foreign objects they might encounter on the ground.

As4 shown in both forms-of the invention, the tendency of the pins 2| and 29 to bend is reduced by positively anchoring them in-the openings 22 of the tread blocks Ill, and spacing the endsof the bushings 25 and 28 relatively closeto the end walls 20 of the recesses I9, and as the aligned openings 22 in the blocks IB form in conjunction with the recesses I9 continuous passages through the blocks III, the pins 2| and 29 can be readily` i and less expensive than the tread bloclgs, the re# placementV of the resilient bushings can be effected with less cost than if they Vwere located in the blocks I6. A further advantage is Sobtained by'` placing the bushings in the linksinstead of in the blocks since the bushings can be'betterin-j spected and tested when in the links.

While the preferred forms of this invention have been described, it willlbe understood that changes in the detail may be made without de' parting from the spirit of the invention and the scope of the appended claims, and it is desired to walls provided with coaxial openings extending parallel to said tread surface andtransversely to the length of said track, a pin extending through each of said recesses and into said openings on each end thereof, said pin being removable but being lixed against rotation in said openings, links for pivotally connecting said blocks, each of said links having a resilient bushing in .each end,

through which one of said pins extends, said bushings being subjected to torsional stressesby.v

an angular displacement of the outer surface of said bushing with Vrespect to the `'original molded position of the inner surface of said-bushing when the center lines of said bushings inrany link.l are aligned with the center lines of Ysaid openings inthe block to which said link is connected, said angular displacement being substantiallyequal to one-half of the operating angular movementof said link'and block and in the opposite directionspaced relation to said opposite walls of said recesses.

2. A track for a track laying vehicle comprising a plurality of one-piece tread blocks pivotally connected by a plurality of links, each block having a top surface adapted to form a track for supporting the wheels of the vehicle and a bottom tread surface, each end of said links having a resilient bushing secured therein, recesses on opposite sides of said block adapted to receive the ends of said links, said recesses having opposite end walls provided with coaxial openings, a pin extending through said openings of each recess and through the bushing in said recess, and said recesses having top and bottom Walls which overhang said pin therein.

3. A track for a track-laying vehicle comprising tread blocks, each of said tread blocks having recesses on opposite sides thereof and a tread surface, each of said recesses having top, bottom, back and end walls which enclose said recesses in all directions, excepting in the lengthwise direction of said track, said recess and Walls having coaxial openings which form in conjunction with said recess a continuous opening through said tread block extending transversely of the length of said track, a continuous pin extending through said recess and xed against rotation in said openings on the opposite ends of said recess, links for pivotally connecting said blocks, each of said links having a resilient bushing in each end thereof Whose outer radial Walls are secured against rotation in respect to said link, one of said bushings in each link being positioned in said recess in one block and the other of said bushings being positioned in an adjacent recess in the adjacent block of said track, said pins in said blocks extending through said bushings and securedl therein against rotation in respect to the inner radial surface of said bushings, and the'end Walls of said bushings being in closely spaced relation to said end walls of said recesses.

RAY S. GARBER. 

